


To Kill An Ocotopus

by SpareBucketTurtle, yuki2810



Category: Assassination Classroom, Katekyou Hitman Reborn!
Genre: 6 years later, Gen, How many tentacles does Koro-sensei have?, Sawada-sensei, Teacher Tsuna
Language: English
Status: In-Progress
Published: 2017-09-26
Updated: 2017-09-26
Packaged: 2019-01-05 13:34:34
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 7,887
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12190923
Author URL: https://archiveofourown.org/users/SpareBucketTurtle/pseuds/SpareBucketTurtle, https://archiveofourown.org/users/yuki2810/pseuds/yuki2810
Summary: To kill an octopus, you need help from the mafia. Seriously. That's why Sawada Tsunayoshi, Vongola Decimo, was assigned to teach the students of Class E to do exactly that. (Does that thing even have eight legs?) Collab from fanfiction





	1. Class 3-E

**Author's Note:**

> This is my collaboration with a friend of mine on fanfiction and decided to add it here as well. Hope you enjoy!

"Dame-Tsuna."

Tsuna's head shot up, sudden panic filling him. He was supposed to be doing his paperwork. "I was just resting my eyes!" he blurted.

Reborn's brow raised, unimpressed. It looked rather unnerving on a seven-year-old. But then again, this was Reborn, so who was he to question him? "Tsuna," he drawled (And wasn't that frightening?). Tsuna sat straight. Reborn only called him by name when something was serious. The child dropped a manila folder on Tsuna's desk. A shiver went up Tsuna's spine as he saw the glint in Reborn's eyes. "You're doing this." Tsuna feared to open that file now.

But if he didn't…

Tsuna snatched the folder up and flipped it open. Staring back at him was the picture of a yellow...octopus thing. "What?" Tsuna said blankly.

Reborn rolled his eyes. "Read it, Dame-Tsuna." Tsuna started reading the file as directed.

_**Subject-62:** _

_**Description:**_   _Yellow, takes on the appearance of an octopus (number of tentacles unconfirmed)? Beady black eyes, always grinning. No known nose or ears. Chromatophore. Wears fancy graduation robes, accompanied by a matching hat and a tie with the symbol of a crescent moon (From his previous action?)._

 _ **Personality:**_   _Surprisingly normal. Often takes on a mocking tone. Has an unusual interest in pornographic magazines (pervert). For further information, contact Karasuma Tadaomi._

 _ **Weakness:**_  ' _Anti-sensei' material. Further information currently being investigated._

 _ **Motives:**_   _Has intentions to destroy the earth one year from 3 April 20XX. (Has already destroyed approximately 70% of the Moon as a warning.)_

 _ **Conditions:**_   _Subject demands to be given free reign to teach a class (Class 3-E of Kunugigaoka Junior High School)._

 _ **Current Strategy:**_   _Class E is to be trained by Karasuma Tadaomi to learn the skills needed to assassinate Subject. Other professionals and hitman will be hired to attempt to eliminate Subject._

Tsuna didn't need to read anymore. He snapped the folder shut to meet Reborn's calculating eyes.

"I didn't think you'd be so determined to take the job," Reborn commented, watching Tsuna's every movement. "I thought you'd reject the job, and that I'd have to force you to do it."

"I changed my mind," Tsuna stated calmly, picking up his pen to continue doing his paperwork. "I'm willing to accept this."

"Why?"

Tsuna looked up.

"You aren't the type to agree to these things unless you're absolutely sure it is safe," Reborn explained. "So why?"

"I don't like it," Tsuna answered, voice tight. "I don't understand why they have to train kids to be assassins. Their lives shouldn't be taken away like that."

"You forget, Dame-Tsuna," Reborn responded, "That potential is best drawn out from a young age. Mafioso always starts training from a young age. You were the same. There's a reason it was decided you be trained as early as possible. You were fourteen at the time."

"Thirteen," Tsuna absently corrected, flinching at the glare Reborn gave him. "But I never had a choice." He ignored Reborn's now smug look. "For me, it was either do or die. If these children are to be trained, I want to make sure they're trained well." He signed another document and then set his pen down, leaning back into his armchair. "I'm aware of how...simpleminded some higher up government members can be. I don't want them to get a class of students killed and cover it up just to save their own reputation."

"I don't care how personal this situation is to you," Reborn said peeking over a stack of paperwork to meet Tsuna's eyes. His gaze was cold and blank, all business. "On a job, your opinions don't matter. Your actions will reflect on your family, but because you are the Vongola Decimo, your actions will reflect on all of Cosa Nostra. You wanted everyone's view of Vongola being the family with the bloodiest history to change, to become more like Primo's vigilante group. Finish the mission the way you believe will help you achieve that dream."

Tsuna was stunned, eyes wide in surprise. "I...Reborn…That...was really cheesy." Tsuna winced at the pain he received immediately after the words left his mouth. "It's true!" Tsuna insisted. His eyes softened. "But thanks. I will."

Reborn smirked, stepping back with a satisfied air around him. "You better." He pulled the brim of his fedora down to shadow his eyes, a smile playing on his lips.

**-To Kill an Octopus-**

Tsuna sighed as he headed for the government building listed in the file he was given. Reborn had promptly kicked Tsuna out of Vongola HQ, shoving him onto a private jet to Japan. Tsuna felt nervous. He was a mafioso. It wasn't normal for Mafiosi to just walk through the front gates into a government building. After talking to the receptionist and being directed up to the top floor (Seventh floor), he has arrived in front of two large wooden doors with golden handles. He knocked on them thrice.

"Come in," he heard. He pushed the doors open.

Tsuna entered the room to see a rather fancy looking office room, though not anything close to the Don Vongola's office back at Vongola HQ. There was a rounded desk in the far middle of the room. Sitting behind it was a middle-aged man with carefully combed brown hair and dark brown eyes wearing a standard suit that everyone in the government wore. His arms were propped up on their elbows, fingers laced together. Tsuna noticed a worn out gold ring on his left hand's ring finger and a gold watch on his right wrist. Not counting the fact that Tsuna knew the man was in charge of the military, he could easily tell that the man was wealthy.

"Yama Arato-san," Tsuna greeted with a small bow of his head. Off to the side, Tsuna could see another man with spiky black hair and dark narrow eyes also wearing a suit. He was watching Tsuna like a hawk. "I believe you requested some...help with a certain situation."

Yama nodded, brown eyes hardening. "I don't like asking criminals for help, but I'm willing to lower myself for such a problem."

Tsuna frowned slightly. "I understand that my kind doesn't have the best morals, but we have better morals than actual criminals, sir."

Yama's lips thinned. "If that's what you believe. Sawada Tsunayoshi, was it? I've read your file. It's hard to believe you've become this sort of person."

"What I believe," Tsuna responded coolly. "Is that we were here to discuss what I was hired for, not my personal life."

"I apologize," Yama didn't sound apologetic at all. "Then back onto topic. This is Karasuma Tadaomi." He gestured at the black-haired man in the room. "He is currently in charge of observing Subject-62. You will be working alongside him for the duration of your...mission." Karasuma gave him a curt nod, and Tsuna returned it. "Am I to assume that you understand the fact that you are working for us is not to be leaked to  _anyone_?"

Tsuna smiled wryly inside. "Of course, sir. The same could be said from my side." Yama stiffened and glared.  _Point for me_ , Tsuna cheered inwardly.

"That is all," Yama said tightly. "You are dismissed."

Tsuna held the urge to snort. That Yama thought he was in charge of Tsuna. The old man didn't even know Tsuna's rank in the mafia! But Tsuna was undercover as a solo hitman, so he couldn't talk back if he didn't want to be fired. Without another sound, Tsuna left the room, letting the door close behind him softly.

**-To Kill an Octopus-**

Tsuna didn't like him.

Asano Gakuhou.

Tsuna had been told to meet the principal of Kunugigaoka Junior High School. Tsuna knew immediately that he wouldn't like the man. His presence itself bothered Tsuna. The man just stood there, with his auburn colored hair gelled back and a poster smile on his face. Yet he was able to make Tsuna's intuition react so strongly. The guy had secrets, everyone did, but this man seemed to have hidden intentions, ones that no normal person would ever think of. Tsuna's seen people like him before, people who wanted,  _needed_ , to be in control. But this man was better than them. He had a mentality even better than those in the mafia. This man knew exactly what was needed to be and stay on top and control the ones under him. And this man, Asano Gakuhou, stood before him now.

"So you are going to accompany...Koro-sensei," the name was said in distaste. "In teaching Class 3-E?" Asano didn't like Koro-sensei then but kept that fake smile for appearance's sake.

"Yes," Tsuna answered, thinking about how easily a normal person would've been tricked by that smile. "I was assigned to that class by..." Tsuna momentarily pondered how much he should reveal. "The government."

Something lit in Asano's eyes. "Then you are aware of the special circumstances of that class and not just a normal teacher."

Tsuna nodded slowly. "I have been trained in hand to hand combat. However, my purpose here is not to slay...Koro-sensei, was it? I've been told to observe his teaching methods and assist or correct him if necessary."

"I see." Asano's lips twitched downward. This type of person also hated those stubbornly loyal to someone else, as Tsuna might've seemed to the government. Tsuna would let him assume whatever he wanted if it kept Asano from attempting to manipulate him.

"If you'll excuse me," Tsuna bowed his head down slightly to imply that he had nothing else to say.

"You're dismissed." Tsuna was starting to hate that line. He exited only to blink in surprise when he saw Karasuma waiting for him against the wall outside the room.

"Karasuma-san," Tsuna greeted. "It's been a while."

Karasuma stared at him. "It's been a few hours."

"Exactly."

Karasuma stared at him for a split second longer before shaking his head in reluctant amusement. "Anyways, I will show you to Class E's classroom. It isn't really a...convenient place to go to."

Tsuna blinked, confused. It was just a classroom, wasn't it? Somewhere in the school?

He was wrong.

Class 3-E's classroom turned out to be a hut on a mountain.

Tsuna examined the room he had just entered. The room was dilapidated, simple wooden walls not even painted over with holes in them, and old desks also made of wood. Some of the desks surfaces weren't even flat. The blackboard seemed to be the object in the best condition in the room.

"You're the one that's going to join us in teaching the class?" a voice chirped. Tsuna blinked at the one who spoke. It was the yellow octopus from the pictures in the file he received. The octopus's grin was more unnerving in person. "You can call me Koro-sensei," Koro-sensei said, holding out a...tentacle for Tsuna to shake.

Tsuna hesitantly shook it. "I'm Sawada Tsunayoshi. I'll...be in your care from now on so please take care of me," he said with a slightly nervous smile. He had never taught anyone before. This being a mission just added to the pressure. "It's a...a pleasure to meet you, Koro-sensei."

Koro-sensei's grin seemed to widen slightly. "The same to you, Sawada-sensei. Why don't you get comfortable while waiting for the students to arrive?"

Tsuna nodded curtly, pulling his hand back as Koro-sensei returned to his desk. Out of the corner of his eye, he saw Karasuma nod his head towards the hallway. Tsuna followed him out of the classroom.

"So?" Karasuma asked once the door closed behind them in a small voice. "What do you think?"

"I'm not sure yet," Tsuna admitted honestly. "But he is rather...interesting in appearance."

Karasuma nodded in understanding. "I see. You can use the time before the kids arrive to get used to the area if you'd like."

"Thank you," Tsuna said.

And that's what Tsuna did. He wandered the perimeters of the small hut (more like a shack) for about half an hour, noting anything of importance, like the open field, any particularly large trees, or potholes that might hinder him in the future. For the next half hour, he skimmed the students' profiles he had been provided with. He memorized names and appearances, not taking note of anything else because he believed the students should be the ones to tell any other personal information.

The students started to trickle up to the mountain soon after. Tsuna had watched from one of the larger trees he found, keeping track of their personalities and their attitude towards others. It was only after Karasuma came to retrieve him that he got down. Karasuma wanted him to introduce himself to the class. Tsuna inwardly grimaced, not looking forward to being watched by about thirty pairs of eyes.

As he entered the classroom, Tsuna glanced over the students. They were watching him, just like he had expected. But really. They were only fifteen or sixteen. Why...Just why were they condemned to this fate?

"Are you alright?"

Tsuna flicked his gaze over to Karasuma at his right. "Yes," Tsuna answered curtly. He turned back towards the class. "Hello," Tsuna started. "I am Sawada Tsunayoshi. I will be assisting this class in," Tsuna's gaze wandered over to the yellow octopus reading inappropriate magazines. He let a small sigh escape. "Necessary skills for the rest of this year." The class was silent, scrutinizing him. "...Any questions?"

A few hands shot up. Tsuna nodded towards a black pony-tailed girl, Yada Touka.

"Are you going to try to kill Koro-sensei?"

Tsuna didn't look towards the said teacher. "Indirectly," he answered shortly. He turned towards a wavy-haired girl, Kurahashi Hinano, meeting her gaze.

"Er, what was your job before this?"

"I am a hitman," Tsuna turned towards the next student with their hand up as soon as the girl's eyes started to widen. This was a turquoise-haired girl, Kayano Kaede.

"Uhm, What exactly are you going to teach?"

Tsuna smiled a smile that held no warmth. "Anything necessary."

"Anything?" A red-haired boy called out. That was Akabane Karma.

Tsuna met his gaze. The kid was challenging him. "Anything," Tsuna answered firmly.

"So you're teaching us to kill, right?"

"Oi, are you after the money too?!"

"How old are you anyway?"

"Are you going to teach us how to make bombs?"

"What about knife throwing?"

Tsuna noticed a hand raised off to the side of the classroom. "Chiba Ryounosuke-kun," Tsuna raised his voice over the students'. "What's your question?" The class immediately silenced, turning their attention towards the said boy. The black haired teen fidgeted under their gazes, hair covering his face now proving to be useful.

"We...Are we going to learn how to use different types of guns?" he asked quietly.

Tsuna hid a genuine smile. "Yes," he answered. "If you have any preference, let me know later on. Any other questions?" The classroom stayed silent. "Good. Today, I'll only be observing to see how things work around here. If you have problems with that, I don't care." Seeing the students' gasps were worth it.

**-To Kill an Octopus-**

The guy just stood there. Watching them. It was kind of creepy actually. Karma nudged Nagisa lightly, turning the blue-haired boy's attention away from their new teacher. "What is it, Karma-kun?" Both of them struck their arm downwards, gripping the anti-sensei knife tightly, as directed by Karasuma-sensei.

"What do you think of him?" Karma asked, jerking his chin towards Sawada-sensei standing at the side of the field.

"We've only known him for an hour," Nagisa chided lightly.

Touka suddenly appeared beside them. "How old do you think Sawada-sensei is?" she asked with a sly smile.

"Nineteen years old," Ritsu's mechanical voice came from Nagisa's pocket.

The three students were taken aback.

"He's an assassin at that young of an age?!" Touka whispered in shock.

He couldn't have heard them speaking; they were too far, but Sawada-sensei turned towards them as if he knew they were talking about him.

Karma tossed a smirk over towards Sawada-sensei. Sawada-sensei surprisingly smiled wryly back. Karma turned back to Nagisa, who had taken his phone out. "What else do you have on him, Ritsu?"

"His hometown is Namimori, Japan. He graduated from Namimori High School," Ritsu continued.

"Did he go to college?" Touka asked when Ritsu didn't continue talking about his education.

"Records show that he flew to Italy," Ritsu replied. "There is no known information of Sawada-sensei entering college in Japan."

"That's surprising," Nagisa said. "You would think that the principal would only allow people with exceptional education to teach."

"Well he probably doesn't care," Kaede commented, joining their conversation. "I mean, we're Class E," she said bitterly. "It doesn't matter if our education is good or bad."

"We don't have time to worry about our education anyways," Karma said with a shrug. "We're busy trying to kill the guy who says he's going to destroy the world. Why would our grades matter?"

"Stop chatting!" Karasuma-sensei barked, interrupting them. They jolted back into position, continuing their downward strike exercise.

**-To Kill an Octopus-**

Irina had arrived late. She had been held up by...other things, such as going out to bars despite it being early in the afternoon. She hadn't been on actual missions in a while, so she liked to play the men at bars, attracting them then tossing them away. She took pleasure in seeing men knocked down a few pegs. At least she made it on time for her own lessons. However, she didn't get the notification about the newcomer.

"Who's the new kid?" Irina asked Karasuma when she entered, looking over at said 'kid' at the other end of the room.

"He's not a new student," Karasuma answered, not looking up from the file he was reading. "He's an assistant teacher and will be helping Koro-sensei teach the academic subjects, as well as helping us teach the assassination subjects."

Irina gave him an unconvinced look. "Really? He looks like a wet behind the ears brat."

"You of all people should know not to judge people by their looks. Besides, he's from the-" Karasuma lowered his voice. "Mafia."

Irina only smirked. "He seems fun to play with," she said, ignoring Karasuma's words. "Let's see what he can do." Getting up, she walked towards the brown-haired young man with the seductive aura she always used for work.

"Hey there…"

The young man turned towards her, giving her a warm smile. "Hello, you must be the other teacher here. I'm Sawada Tsunayoshi."

"Well then, Tsunayoshi-kun," she purred his name out, earning an uncomfortable fidget. "I'm Irina Jelavic or Jelavic Irina."

"Bitch-sensei!" Karma called out from the back of the room with a mischievous smirk. "You're never going to succeed, you know! Stop trying!"

Irina's eye twitched. "You little brat!" she growled angrily. She fought the urge to go beat the kid up in order to smile sweetly at Sawada. "Ignore them, Tsunayoshi-kun."

Sawada only blinked at her. "Tsuna is fine, Jelavic-san."

Irina inwardly frowned. The boy wasn't reacting as expected at all. She kept smiling. "Why don't we do something together after class? I guarantee it'll be fun," she winked.

Sawada furrowed his brows, looking upset. "I'm sorry Jelavic-san, but I have no interest in romance. I'd appreciate it if you didn't flirt with me."

"Hah! You got re-jec-ted, Bitch-sensei!" Now, Irina openly glared at Karma. She turned back to Sawada with a cool expression. "Well, it was worth a try," she said offhandedly. "You're not so bad, Tsunayoshi-kun."

"Just Tsuna is fine," Sawada-Tsuna repeated politely. "And thank you for the compliment." He glanced at his watch. "I'm sorry, but I must be going soon. Goodbye." Without a glance back, he was out the door.

Irina watched him leave, before turning onto a certain someone who had pissed her off the whole conversation. "Karma, you little brat!"

The red-haired menace stuck his tongue out at her, dashing out of the room with a snicker.

**-To Kill an Octopus-**

Tsuna grimaced as he settled into a comfortable armchair. It had been a long and tiring day even though he did nothing. It was probably the fact that he had to deal with so many authority figures. He tilted his head from side to side, stretching his neck and yawning. He just hoped the kids wouldn't be that hard to teach, but knowing his luck...they probably were.

Tsuna almost jumped out of his seat when a familiar ringing was heard. He fumbled for his phone and answered the call hurriedly once he saw the caller ID. "H-Hello? Reborn?"

" _Dame-Tsuna, did I just hear you stutter?"_

"No!" Tsuna yelped. "But...why did you call?"

" _Stupid, I had to make sure you didn't mess anything up. How was it so far?"_

Tsuna calmed down. "Well, Koro-sensei isn't an evil mastermind villain. That's more like the principal. Karasuma-san is easy to get along with, and Jelavic-san is rather...Well, I haven't known her for even longer than ten minutes, but she tried to seduce me. It doesn't really leave the best impression, but I know she was only trying to test me."

" _Seems like you've had quite the day,"_  Reborn commented dryly. " _Good luck teaching a bunch of brats. I'm sure you'll have trouble. I did with you."_  He hung up.

Tsuna slumped down in his seat, groaning.


	2. Sawada-sensei

**Summary for the Chapter:**

> To kill an octopus, you need help from the mafia. Seriously. That's why Sawada Tsunayoshi, Vongola Decimo, was assigned to teach the students of Class E to do exactly that. (Does that thing even have eight legs?)

Tsuna hated rainy days.  _No offense, Takeshi_ , Tsuna thought as he trudged up the mountain. He lamented the thought of cleaning the mud off the bottom of his shoes. He determinedly ignored the voice in his head reminding him to never let Reborn find out that his outfit was being anything less than spotless. Nonetheless, it was inevitable that at least a few drops of water soaked into his suit. Even with his expert umbrella wielding skills, Tsuna was sure even Reborn wouldn't be able to dodge every drop.  _So there_ , Tsuna pouted petulantly in his mind as he pulled his umbrella lower. But he would still need to get rid of any trace of mud because the brunet was sure his not-so-former tutor would pull off a surprise visit and would definitely punish him if- _when_ -he found out about the mud.

Tsuna shook his head with a shudder. No, he told himself, he couldn't be distracted. He had a class to teach.

Tsuna soon arrived at Class E's building, only to see a large group of teenagers smiling and laughing despite the dreary atmosphere. Unfortunately, this didn't help Tsuna's own mood. He needed coffee. Badly. Anything to get rid of the smell of petrichor. He dragged himself into the old school building and made a beeline for the teacher's lounge, not caring that he seemed very rude for not returning the students' greetings.  _Reborn's going to kill me for these horrible manners_ , Tsuna grimaced. Yet another thing Reborn would pick on him for. Automatically, his arm reached for the jar of coffee powder as he started to boil water in the electric kettle. He sat down, his left leg fidgeting and his right hand tapping against the side of the chair as he waited with anticipation for the water to finish boiling. Minutes later, the brunet heard the click of the machine finishing its job and stood up immediately. He poured the hot water into his cup and began stirring.

"You really love your coffee, don't you?"

The only thing that kept Tsuna from jumping around was the fact that he would've spilled the burning liquid on himself. Instead, he slowly turned around. Karasuma stood in the doorway, leaning against the frame with his arms crossed. "Hn," Tsuna grunted, not caring that he sounded a lot like his Cloud Guardian.

"Not a morning person, I take it?" Karasuma asked as he pushed himself off the frame into the room, moving to prepare his own cup.

Tsuna took a long sip of his drink in response, feeling satisfied as warmth filled him. "Yes," he replied. "Especially with the rain. The cold air makes me feel very...stiff and tired."

"I'll help you with that!" Tsuna felt something massaging his shoulders, and he looked up to see a giant yellow head. He  _did_ drop his cup of coffee this time, but Koro-sensei's Mach 20 speed caught the cup with all of its contents still inside it. Tsuna had been caught off guard, and the wide grin on the octopus's face did not help his nerves one bit.

"K-Koro-sensei," Tsuna almost yelped, but his pride kept him from doing so. "I'm fine. Just fine." He stepped away, taking back his cup. "Coffee is enough for me." He paused. Koro-sensei looked downtrodden, like a child whose favorite toy was taken away. "Thank you, though," he added. Koro-sensei brightened. Like a child, indeed.

"What exactly do you intend to do here, Sawada-san?" Karasuma asked, eyeing Tsuna calculatingly. Tsuna knew that look. Karasuma was trying to figure out what exactly Tsuna would be able to contribute to this special classroom. "You were observing the whole day yesterday. What do you think they need to work on?"

Tsuna sighed inwardly. No matter how open-minded Karasuma was, he was still suspicious of the mafioso taking on a government job. He was blatantly trying to reveal Tsuna's 'true' personality as well as silently challenging Tsuna, asking what he was going to do about it.  _I never want to make this guy my enemy_ , Tsuna prayed in his mind to any deities that would listen, for Tsuna could recognize how capable a fighter and strategist Karasuma was. But then again, Karasuma was part of the government, the law, and therefore already an enemy. Tsuna fought the urge to slap his hand to his face.

Tsuna instead forced a slight smile on his face, earning an irritated eye twitch from the dark-haired man. So Karasuma was the type of person who appreciated seriousness when the situation called for it. Tsuna could easily infer that this was Jelavic Irina's (Or was it Irina Jelavic since she wasn't Japanese?) fault, considering the way she introduced herself to Tsuna the day before. Yes, if his only co-workers were the immature Koro-sensei and flirty Jelavic, then no wonder Karasuma would immediately assume Tsuna's attempt to maintain a pleasant personality was an act of mocking his question. Tsuna respected Karasuma though, for being able to put up with all of Koro-sensei's, Jelavic's,  _and_ the government's shit, so he wouldn't call the man out on that assumption and answer honestly. "As I said yesterday, I will teach the students whatever they want me to teach, as well as whatever needs to be taught." Tsuna stopped for a moment to take a sip of much-needed coffee. "Of course, while I am willing to help with academic subjects, I'm sure Koro-sensei has them well covered," he stated dryly.

Said octopus-like teacher laughed in what he probably thought was an evil way, rubbing his hands (Tentacles?) together with a "Nurufufufu!" Tsuna was glad that despite the similar laugh, Koro-sensei was  _nothing_ like his male Mist Guardian.

"And Karasuma-sensei is setting the foundations of the students' combat ability," Tsuna continued, tilting his head towards the man in acknowledgment. "I can see that the students are only just warming up to Jelavic-san-" Tsuna hid a smirk by taking a sip of his coffee when Karasuma's eyebrow rose in surprise at Tsuna's accurate insight. He set the cup back down on the table. "-so I can help with languages. I know quite a few myself. But I believe I can best help when it comes to specialties."

"Specialties?" Koro-sensei echoed. Tsuna didn't know how, but Koro-sensei's beady eyes managed to narrow with interest.

Tsuna gave a thin smile. "As I said yesterday," he repeated. "Whatever they want to learn, what they want to specialize in, what they're passionate about." The faint noise of the starting bell from the main Kunugigaoka building could be heard in the distance. Tsuna stood up from his seat, eyes narrowing. "As well as anything necessary." The familiar sensation of his Dying Will Flames burned inside him as his eyes flashed orange for a split second. " _Anything_."

**-To Kill an Octopus-**

In the corner of his eye, Nagisa caught sight of the class's new assistant teacher entering the room. Sawada-sensei didn't look like he could kill anybody. He had wide does-like brown eyes and fluffy brown hair that made him look (dare he say it) like a small animal, especially considering his short stature for his age. Not only that, but Sawada-sensei looked oddly out of place in a suit.

Was he teaching them this morning?

"Tsuna-kun!" Bitch-sensei called out excitedly as she entered after the man. "Are you teaching with me today?"

"I'll be helping," Sawada-sensei corrected, a strained smile on his face. He moved off to the side of the classroom, leaning against the wall as he observed the class.

An elbow suddenly jabbed into Nagisa and he bit back a yelp. He turned to see Kaede rub the back of her neck sheepishly, mouthing an apology. She leaned over from her seat. "What do you think of him, Nagisa-kun?" she whispered.

Nagisa shrugged, taking out his notepad where he wrote all of Koro-sensei's weaknesses. He flipped it all the way to the last page, considering whether or not he should start a list of facts they knew about Sawada-sensei in case he turned out to be another two-faced person like Bitch-sensei had been. After all, he was still a complete mystery to them. "He seems nice," Nagisa told the green haired girl. "But Sawada-sensei could be pretending. He doesn't seem to be against us learning anything like other adults is, though."

Tomohito leaned forward from his seat behind Nagisa. "Maybe he's also only after the money, but unlike Bitch-sensei, he intends to use us and takes all the credit. Kinda like what Terasaka did with you." Nagisa flinched at the reminder.

"Oi, quiet down and sit, brats!" Bitch-sensei shouted at the class, personality a complete one-eighty from when she was speaking with Sawada-sensei. "Today, we're continuing with English! It's the language the whole world would agree is the main language. It's on a need-to-know basis if you're going to be an assassin."

The class proceeded to learn about the differences between 'L's and 'R's, 'B's and 'V's, and more at the risk of Bitch-sensei's lips. However, Nagisa did think the dramas Bitch-sensei showed them, despite the fact that they were all about sex and seduction, were rather helpful. Unfortunately, Bitch-sensei became very frustrated when Kimura was unable to differentiate the 'L' and 'R' sound of the word English word 'really'.

"Tsuna-kun!" Bitch-sensei practically whined, and really, that behavior wasn't unexpected considering her personality. "You can say it, right? Can't you help me make them do it right?"

Sawada-sensei had been staring off into space out the window when his name was called, causing his head to jerk up almost comically when he came into attention. The startled expression was quickly covered up with a small smile. "Of course," Sawada-sensei answered smoothly as if he had never been distracted. "' _Maji de_ ', in English is said as ' _really_ '. In a sentence, ' _You all really need to learn English_ ,' which translates to 'You all really need to learn English'."

Silence resounded in the classroom.

Sawada-sensei blinked. "Is...Is something wrong?"

The class erupted into murmurs of compliments at his English, how fluent he was, how his Japanese accent didn't show at all. Even Bitch-sensei was visibly impressed.

"Not bad at all, Tsuna-kun," she commented. "How long did it take you to get to this point?"

"Well, I was never the best student," Sawada-sensei admitted easily. "But I was forced to truly learn five years ago when I went to visit England. I was told to lose the accent or else-" He cut himself off, looking unsure of whether or not he should finish that sentence. He eventually decided not to, as he continued with, "Anyways, English comes easily to me now." He paused to think. "As does Italian, Russian, French, Spanish, German, and Chinese." He ducked his head when the class gasped. "I'm not as fluent in half of those, though," he added, trying to be modest. It didn't help.

"Are knowing a lot of languages really that necessary for being an assassin?" Hinano asked, dispirited because she wasn't having the best luck with learning a second language.

"N-No! No, not at all!" Sawada-sensei blurted out with wide eyes as if just realizing how discouraging his words might have sounded like. "There are different kinds of assassins," he was quick to explain. "Every assassin has their own specialty. Of course, to most civilians, the first thing that comes to mind is someone wearing dark clothes who sneaks up behind people with a knife, correct?" He earning some sheepish nods. "In truth, assassins, the more professional they are, the less need they have to sneak in the shadows." He paused for a moment to let the fact soak in. "As I was saying before, all assassins have their own specialty. For example, the Poison Scorpion uses what is called 'Poison Cooking'. The food she makes is quite literally toxic. Then there's Moretti the Murdered, who is famous for playing dead and catching his targets off guard. Because of this killing method, practically no one actually knows who he is. The infamous Trident Shamal doesn't even need to come into contact with those he assassinates. He uses disease holding mosquitos that have a trident-shaped stinger, which is what he's named after. As you can see, their weapons of choice are all unique. They usually use what feels most comfortable or what they're most confident with.

"That's what I'm here for," Sawada-sensei raised his voice to make sure everyone in the classroom heard, and Nagisa didn't miss the way all his classmates' backs straightened at his authoritative tone. "I'm not here to make sure you pass this class, and I'm not here to assist in killing Koro-sensei. I'm here to help you find and improve the skills you already have and turn them into effective weapons. I'm here to ensure that none of you let those weapons go to waste." His dark brown eyes seemed to burn into a deep amber color. If the afternoon sun wasn't shining through the windows behind the man, Nagisa would've sworn his eyes were glowing. "And most important of all, I'm here to see that you all will survive." The sheer determination laced through that single word sent shivers up Nagisa's spine. In the corner of the blue-haired boy's eyes, he caught sight of Karma reacting similarly, before leaning forward with a fascinated expression. Just that motion caused a second jolt of something run through Nagisa's body, for in this moment, he didn't know whether he should fear for Sawada-sensei, or for Karma. Forcing himself to focus his attention back on Class-E's new teacher, Nagisa watched as the whole image (bright and strong and filled with purpose) broke with a single blink. Orange eyes disappeared and the sun no longer shined at the right angle to produce the same image. Sawada-sensei's previously piercing gaze now flickered between students with an uncertain air. "Erm... Are there any more questions?"

**-To Kill an Octopus-**

"Sawada-sensei's really weird, isn't he?"

Nagisa glanced up to see Hiroto approach and take a seat next to him under the tree Nagisa ate lunch at every day. Tomohito was taking a nap in the shadow of a tree on the other side, and Karma was sitting up in a branch doing who-knows-what. So Nagisa took it in stride when Hiroto stretched out his legs and rested his hands behind his head, leaning against the trunk of the tree. "What do you mean, Maehara-kun?"

"Well," Hiroto mused, "He's all wimpy at first, then he turns all serious like Karasuma-sensei, then he goes back to being a wimp! It's like he can't decide on whether he wants to be badass or a loser."

Nagisa sweatdropped at his classmate's choice of diction. "Well, at least he's not like a second Bitch-sensei."

As if on cue, they could hear Sumire's voice call out loudly from the classroom. "See you after lunch, Bitch-sensei!" The shouted retort from Bitch-sensei was full of insults and swear words.

A scoff came from above them. Karma peered down at them with a smirk. "Don't write Sawada-sensei off just like that. If Bitch-sensei wasn't as one-sided as she seemed, what makes you think Sawada-sensei will be as well? Besides, the wimpiness and badassery you were talking about? That personality change is proof that he's more than he seems." A feral grin grew on his face. "It's just a matter of seeing if the wimpiness makes him weak and if the badassery makes him strong." Karma tilted his head towards the classroom to gesture at the teacher in question, who had propped open the window of the teacher's lounge to survey the students. A slight frown pulled his lips down as his eye's flickered from one end of his vision to the other as if he were looking for something.

"What're you guys looking at?"

Hiroto yelped and even Nagisa jumped at Yuuma's sudden appearance. Yuuma huffed out a laugh and Karma snickered at their reaction. "Isogai-kun, please don't do that," Nagisa admonished, hand over his heart. Then he added, "And we're talking about Sawada-sensei. He seems nice, and a little uncomfortable about being around all of us. But he changes completely sometimes, so we're wondering which side of him is real or fake, like how Bitch-sensei acting really nice in front of Koro-sensei was fake."

"Huh." Yuuma dropped down to the ground and sat with his legs crossed. "I think both sides are real." Hiroto sent him a skeptical expression while Karma looked over with interest and Nagisa flipped open his notepad to take notes. The more information Nagisa could gather on how everyone saw Sawada-sensei, the surer he could be on what kind of person he really was. They'd need as much ammunition as possible against him if Sawada-sensei turns out to be someone trying to hinder their education and assassination.

"I mean it," Yuuma addressed Hiroto's skepticism. "Sawada-sensei sounded like he honestly wanted to teach us. Why else would he promise  _anything_? He even cheered Kurahashi-chan up when she was feeling discouraged even though he didn't have to! If he truly didn't care about being a teacher, he wouldn't have bothered doing that."

"Yeah, but he also said he'd be trying for the ten billion!" Hiroto voiced what Tomohito had proposed during class, refusing to believe Sawada-sensei wouldn't try to steal the bounty. "He said he'd be killing Koro-sensei 'indirectly', which probably means he'll get others to do the killing to not get his hands dirty, just like Bitch-sensei, only more open about his intentions."

Yuuma sent over a look that said,  _I question your intelligence, sometimes_. "When he said 'indirectly', he meant will attack Koro-sensei through teaching us," he explained with patience. "Sawada-sensei seems like the type of person who wants work done right; therefore, he does the work himself. By teaching us well, we'd be able to defeat Koro-sensei. It's a win-win for both Sawada-sensei and us."

Hiroto was still dubious. "Why wouldn't he want part of the ten billion?" After all, no matter how much anyone denied it, money did help people go places.

Yuuma was stumped, so Nagisa picked up after him. "Maybe Sawada-sensei doesn't need the money? Koro-sensei can't be the only person with money on his head. Perhaps he was on another job before this? And wouldn't the government have set certain conditions before letting him teach us? They wouldn't let him take too much of the money if they let him take any at all," the blue haired boy pointed out. He received shrugs back from his classmates.

"Aaahh," Hiroto sighed and rolled over onto his stomach. "Whatever. I don't want to think about anymore. When the time comes and Sawada-sensei turns out to be Bastard-sensei to match with Bitch-sensei, we'll find a way to deal with it." And the conversation pretty much ended, moving onto another topic as Tomohito awoke.

But Nagisa exchanged glances with Karma before looking back over at where Sawada-sensei was turning away from the window. Orange eyes met blue for a split second and Nagisa couldn't help but hope that they would never have to 'deal' with Sawada-sensei.

**-To Kill an Octopus-**

Tsuna froze as the door of the room he was about to enter was roughly shoved open hitting the wall with a loud 'BANG'. Jelavic slammed the door back to a closed behind her and marched past Tsuna with an irritated expression, not even acknowledging his presence. Tsuna blinked, confused with her agitation, and slid the door open once more. He did so slowly and quietly, a big difference from when Jelavic exited. Tsuna entered the room to see Karasuma closing his laptop and shuffling through papers, clearly having finished up whatever work he had for the moment.

"Good afternoon, Sawada-sensei!" Koro-sensei chirped.

Tsuna smiled courteously back, now in a better mood to deal with the octopus now that it wasn't dreary and raining like it had been in the morning. "Good afternoon, Koro-sensei, Karasuma-san. And please, just calling me 'Tsuna' is fine."

Karasuma raised a brow at the familiar nickname Tsuna offered. "Good afternoon, Sawada," the serious man instead greeted.

"Tsuna-sensei it is, then!" Koro-sensei easily accepted. "I'm going to Shanghai for some almond jelly. Would you like me to get you some since it's your first day as a teacher?"

Tsuna glanced over towards Karasuma, uncertain about how he should answer. The other man took it all in stride, not even looking up from his papers. "No, thank you," Tsuna finally said. "Is there anything I should do during the break?"

"Not much," Karasuma responded, standing up. He tucked his stack of papers into a folder and set it inside a desk drawer. "Do whatever preparations you think will be needed for your short class later this afternoon. Other than that, this is your lunch break as well, not just the students'."

"Oh, I see…" Tsuna had no idea what to do with this time. He had already prepared for his class before he left his apartment. It was a habit ingrained in him by Reborn to have at least a vague schedule if nothing else set in his head, not that it would be hard to think up of a lesson on the spot. But as it was the first day, an introduction to assassination, in general, would be enough, and he wanted to get to know the students by asking about what interests each one had. Doing that would also bring him a step closer to helping the students find the right weapon.

"Well, then. See you later, Sawada," Karasuma nodded curtly and took his leave, not deigning to give Koro-sensei another look.

Koro-sensei didn't seem to be offended at all. "I'm off too! Let me know if you need anything, Tsuna-sensei!"

Those were the words Tsuna was waiting for. "Actually, Koro-sensei, there was something I've been thinking about for quite a while." Koro-sensei's yellow skin faded into a pastel blue, delighted that he could be of some help. "Why exactly are you trying to destroy the world?" Tsuna had asked it innocently enough, and surely, he couldn't be the first person to ask.

Koro-sensei's bright blue dulled to a sick looking gray, but his usual wide smile never faltered. "Trying? I don't need to try to do anything. I  _will_ destroy the world."

It was obvious Koro-sensei didn't plan on answering that question, so Tsuna pressed on. "Then, what intentions do you have behind teaching this class if you're going to destroy the world anyway?"

Tsuna didn't need his Hyper Intuition to tell him that the tension between them suddenly skyrocketed when Koro-sensei didn't reply immediately. Yet...his Intuition was trying to alarm Tsuna of  _something_.  _It has nothing to do with Koro-sensei_ , Tsuna was quick to deduce.  _And he doesn't seem to notice anything off either._  Without waiting for Koro-sensei's response, Tsuna headed to the window and pushed it open. Looking outside, he could only see students. A small group of students with bigger builds whom Tsuna would have been scared of when he was in middle school gathered at one end of the clearing in front of the schoolhouse, playing on their portable game devices. The boy who led the group was named Terasaka Ryoma if Tsuna remembered clearly (And he  _better_ remember clearly, a voice that resembled Reborn's echoed in Tsuna's head). A circle of girls was playing with a jump rope near the center, where there was more room. Tsuna could make out a couple heads bobbing up the mountain, returning from buying lunch. On the other end of the clearing, another group of boys hung out under a larger tree. They were simply talking, though one was sleeping. Akabane (The red-haired boy made a memorable impression on Tsuna the day before) was up in the tree, lying on a branch, completely relaxed.  _He's a lot like Kyouya_ , Tsuna thought a touch wistfully, thinking about how his friend-not-friend challenged everyone he interacted with, like how Akabane subtly did to Tsuna the day before.

"Something wrong, Tsuna-sensei?"

Tsuna nearly forgot that Koro-sensei never answered his question, but it didn't matter anymore. He shouldn't have expected any sort of answer from the first place. It didn't hurt to try, though. His Intuition still tugged at Tsuna, and it bothered him.  _A potential danger is near_ , it told him. And Tsuna's own thoughts finished with,  _near these precious children_.

"...Nothing," Tsuna murmured quietly, but he was sure Koro-sensei heard anyways. He turned away from the window to face his target once more. "Didn't you want almond jelly?" he gently reminded.

Koro-sensei eyed Tsuna speculatively before saying, "Oh! That's right! Thank you for reminding me, Tsuna-sensei!" It was as if Tsuna's one-sided interrogation never happened at all. But that was fine. "By the way, your eyes are orange, did you know?"

A hand reflexively raised to his face, covering his Flame tempered eyes, but Koro-sensei had already disappeared in a blur. Slowly lowering his hand, Tsuna allowed his thoughts to drift again.

Shiota Nagisa.

That was the name of the boy with those sky blue eyes, wasn't it?

A small smile graced Tsuna's lips. Akabane wasn't the only one that reminded Tsuna of someone else. Shiota wasn't any good like him, but Tsuna was sure that even Reborn would agree that the boy had the same potential that Tsuna did.

* * *

_Chapter Fin._

* * *

**Omake**

_One...Two...Three...Four...Fi-_

Koro-sensei walked towards the opposite end of the blackboard to point something out.

_One...Two...Three...Four...Five...Six...Seve-_

Koro-sensei stepped towards the desk of the student sitting in front.

_One...Two...Three...Fo-_

Koro-sensei stepped backward and turned to face the blackboard.

_One...Two...Three…Four...Fi-_

Koro-sensei had turned to face the class once more.

_Dammit!_

Tsuna let his head drop to hit his desk with an audible 'THUNK', earning the attention of everyone in the room.

"Tsuna-sensei? What's wrong?"

"It's nothing," Tsuna groaned.

"If you say so."

Koro-sensei continued to teach.

_One...Two...Three...Four...Five_

**Author's Note:**

> Remember to comment and tell me what you think! Oh and I'm Yuki2810 from fanfiction just to be clear if it's not already from my name lol


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